Conventionally, solar battery module devices with the following configuration are used at various places and for various purposes. A transparent substrate (glass) is arranged at a light-receiving side, plural solar battery cells connected in series, or in parallel, are arranged on the back side of the transparent substrate, and the solar battery cells are then sealed with a sealing resin to constitute a solar cell module. A frame is fitted to an outer-edge portion of the solar cell module, thereby providing a solar battery module device. Bigger and bigger solar battery module devices are being manufactured in recent years with the aim to lower cost per unit output and to shorten the time required for production and line connection work. However, with an increase in the size, the load resistance performance of the surface of the transparent substrate degrades. In this solar battery module device, a predetermined strength is maintained by the transparent substrate and the frame.
Solar battery module devices are generally installed on a construction, such as a house and a building, where they are exposed to the weather. When, for example, snow accumulates on the top surface the solar battery module device, a positive pressure that is operative to vertically press down the solar battery module device acts on the solar battery module device. On the other hand, a negative pressure that is operative to push the solar battery module device acts on the solar battery module device due to wind and the like. Because the top surface of the solar cell module, which functions as a light-receiving surface, has a wide planer structure with a large area, the module is vertically bent in a curve when receiving the positive pressure and the negative pressure.
Various techniques have been conventionally employed to avoid breakage of the module due to downward bending thereof by the positive pressure that is operative to vertically press down the module. One such conventional technique proposes to provide a reinforcing frame on a back surface of the module. In this configuration, when the module is bent downward, the module is stopped from being bent by more than a predetermined amount, by the reinforcing frame, and thus breakage can be prevented (see, for example, Patent Document 1).    Patent Document 1: Japanese Patent Application Laid-open No. 2004-6625